Glow discharge tube having planar main electrodes and planar auxiliary electrodes



July 25, 1967 s. M. FROUWS 3,333,137

GLOW DISCHARGE TUBE HAVING PLANAR MAIN ELECTRODES AND PLANAR AUXILIARYELECTRODES Filed July 28, 1964 INVENTOR.

SIMON M. FROUWS United States Patent 3,333,137 GLOW DISCHARGE TUBEHAVING PLANAR MAIN ELECTRODES AND PLANAR AUXIL- IARY ELECTRODES SimonMari Frouws, Emmasingel, Eindhoven, Netherlands, assignor to NorthAmerican Philips Company, Inc., New York, N. a corporation of DelawareFiled July 28, 1964, Ser. No. 385,745 Claims priority, applicationNetherlands, Aug. 28, 1963, 297,242 ,2 Claims. (Cl. 313-198) Theinvention relates to a glow discharge tube comprising an ignition anodeand a control-electrode near the anode, while the anode and the cathodeare parallel plates.

The tubes of the kind set forth of a construction hitherto known arepractically suitable for manual mounting, so that their price iscomparatively high. The main electrodes are formed by round platesextending parallel to the bottom of the tube. The manual mountingrequires, in addition, comparatively great dimensions, since otherwisethe accuracy of the electrode spaces is insuflicient.

One of the problems involved in the industrial use of the glow dischargetubes is their price. The price can be most easily reduced by automatedmounting. A second problem of industrial use are the dimensions,particularly because the competing transistor has advantages in thisrespect. The glow discharge tube, however, is more advantageous withrespect to thermal loadability and the insensitivity to temperaturefluctuations.

The invention has for its object to provide a construction which isadvantageous with respect to the known constructions of glow dischargetubes.

In a glow discharge tube comprising an ignition anode and acontrol-electrode near the anode, in which the anode and the cathode areparallel plates, all electrodes are, in accordance with the inventionformed by plates and are welded in line with the electrode leads in thebottom of the tube, while both the ignition anode and thecontrol-electrode are at right angles to the plane of the main anode andthe main cathode and reach into incisions of the main anode and the maincathode so that with respect to the electrode system the tube is quitesymmetrical.

The incisions in the main anode and in the main cathode are preferablyformed from the free ends of the same, while on the rear side thecathode is coated with a material of higher discharge potential in orderto ensure the start of the auxiliary discharge on the front side.

The construction according to the invention is particularly suitable forcarrying out a method in which the electrodes with the supply Wireswelded thereto are held in a jig, after which a bottom of powder glasswith openings for accommodating the electrode through-connections isslipped onto said through-connections and fused thereto simultaneouslywith the fusion of the bulb to the bottom of powdery glass.

The invention will be described more fully with reference to thedrawing, the sole figure of which shows a glow discharge tube accordingto the invention partly in a developed view.

Referring to the figure reference numeral 1 designates a bottom ofpowdery glass and 2 the glass bulb, which tapers upwardly in a sealedpoint 3. The cathode 4 is butt-welded to the end of the current supplywire 5 and the anode 6 to the end of the current supply Wire 7. Theignition anode 8 is welded to the end of the current supply wire 9 andthe control-electrode 10 is welded to the end of the current supply wire11. The ignition anode 8 reaches in the incision 12 of the cathodewithout projecting in the anode-cathode space. The primer-electrode 10reaches in the incision 13 of the anode, also without projecting in thespace between the anode and the cathode. The cathode 4 is coated on therear side with a nickel layer 14. For reasons of symmetry the anode 6 iscoated on the rear side with a nickel layer 15. Otherwise, theelectrodes are made of molybdenum sheet. The distance between the mainanode and the main cathode is 1.5 mms. and the tube is filled with argonof mms. Hg. The tube contains, in addition, lac. of tritium in order toavoid an excessively long delay in the ignition of the controldischarge.

When the tube is assembled, the electrods are first arranged in a jigand the bottom 1 is fused to the current supply wires simultaneouslywith the bulb 2 to the bottom 1. The bulb 1 is a straight length of tubeof a diameter of 6 mms., which serves, in addition, as an exhaust tube.After the pumping operation, the surfaces of the electrodes are cleanedby discharges by volatilization so that a dark deposit is produced onthe wall of the bulb. The tube of the size indicated above has ananode-cathode break-down voltage of more than 280 v. and anauxiliaryanode discharge voltage of about v. The burning voltage is 100v. and the operational current is 3 ma., and the current from the anodeto the control-electrode 10 is required for avoiding delays in theignition in the main discharge path is 10 ,ua. The tube is suitable foran ignition frequency of nominal 25 kc./s.

What is claimed is:

1. A glow discharge tube comprising an envelope, an ionizable medium anda substantially symmetrical electrode system within said envelope, saidelectrode system comprising spaced, parallel plate-shaped electrodes oneof which constitutes an anode and the other a cathode, each of saidelectrodes having an incision therein, a plateshaped ignition anodeextending substantially at right angles to and into the incision in thecathode electrode without extending into the space between the cathodeand anode, a plate-shaped control electrode extending substantially atright angles to and into the incision in the anode without extendinginto the space between the cathode and anode, and lead-in conductors foreach of said electrodes extending through a base portion of saidenvelope and integrally connected to the respective electrodes.

2. A glow discharge tube comprising an envelope, an ionizable medium anda substantially symmetrical electrode system within said envelope, saidelectrode system comprising spaced, parallel plate-shaped electrodes oneof which constitutes an anode and the other a cathode, each of saidelectrodes having an incision therein extending from an edge of saidelectrode, said cathode electrode being coated on the side remote fromthe anode with a material having a higher discharge potential than thematerial on the side facing the anode, a plate-shaped ignition anodeextending substantially at right angles to and into the incision in thecathode electrode without extending into the space between the cathodeand anode, a plate-shaped control electrode extending substantially atright angles to and into the incision in the anode without extendinginto the space between the cathode and anode, and lead-in conductors foreach of said electrodes extending through a base portion of saidenvelope and integrally connected to an edge opposite the incision ineach of the respective electrodes.

References Cited UNITED STATES PATENTS Latour et a1 313-198'X Vance313-198 Stieritz 313198 X Kolb et al. 313-198 X

1. A GLOW DISCHARGE TUBE COMPRISING AN ENVELOPE, AN IONIZABLE MEDIUM ANDA SUBSTANTIALLY SYMMETRICAL ELECTRODE SYSTEM WITHIN SAID ENVELOPE, SAIDELECTRODE SYSTEM COMPRISING SPACED, PARALLEL PLATE-SHAPED ELECTRODES ONEOF WHICH CONSTITUTES AN ANODE AND THE OTHER A CATHODE, EACH OF SAIDELECTRODES HAVING AN INCISION THEREIN, A PLATESHAPED IGNITION ANODEEXTENDING SUBSTANTIALLY AT RIGHT ANGLES TO AND INTO THE INCISION IN THECATHODE ELECTRODE WITHOUT EXTENDING INTO THE SPACE BETWEEN THE CATHODEAND ANODE, A PLATE-SHAPED CONTROL ELECTRODE EXTENDING SUBSTANTIALLY ATRIGHT ANGLES TO AN INTO THE INCISION IN THE ANODE WITHOUT EXTENDING INTOTHE SPACE BETWEEN THE CATHODE AND ANODE, AND LEAD-IN CONDUCTORS FOR EACHOF